Sourness is one of the five basic tastes, alongside sweetness, bitterness, saltiness, and umami. It is primarily detected by taste buds on the tongue, which respond to acids found in various foods. Common sources of sourness include citrus fruits like lemons and limes, as well as fermented products like yogurt and sauerkraut. The sensation of sourness can indicate the presence of spoilage in food, as many spoiled items become acidic. This taste can also enhance flavors in cooking, balancing sweetness and adding complexity to dishes. Sourness plays a significant role in culinary traditions worldwide.